Yeah, I think that's why it works out for me... I don't always go for the comics, but really anywhere where there is a heavy concentration of print/ink. I usually find some good dark or print heavy frames (in the comics) and it serves me well.
As a side note, I have also stropped with a print heavy section of the yellowpages a few times... I'd have to experiment over a longer time period, but it seemed to be working in a similar way.